DSA Arms (the ones that make FAL rifles) are selling "South African Beretta mags" that are pre-ban (15 rounders) for about 50 dollars a pop. They are probably surplus S. African military or police (for the Z88) and are in like-new conditon (I picked up some so I can affirm this). They are supposedly (according to the Kokalis articles) more durable than factory Beretta mags. From what I read in a review in American Rifleman last year on the SP1, the SP1 will take Beretta 92 mags, and since the Z88 is a copy of the Beretta 92, the Z88 mags should fit into the SP1 (which, along with the Z88, is a must get for me).
I guess I too would be worried about spare parts and service, but from what I saw on their site, there was little information in those two areas that was divulged. I hope to see this company suceed, but it is a line (specifically the 9mm Z88 and SP1 full size) that is competing in a saturated market where the magazine capacity limitations have also made their size unnecessary.
The 9mm caliber is also considered to be somewhat weak when compared to the .40, .357 SIG and 10mm calibers. Perhaps the CP1 (polymer frame compact), SP1 Generals (compact) model and the .40 S&W caliber SP2 will gain popularity.